AutoCodes – GMC – C0805 2018 GMC Sierra

C0805 2018 GMC Sierra Code - Control Module Power 2 Circuit

Quick Answer

The vehicle control modules or sensors monitor the system voltage to verify the system voltage is within the normal operating range. Common causes include Battery voltage, Faulty Control Module, Control Module harness is open or shorted. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: C0805 2018 GMC Sierra indicates Control Module Power 2 Circuit.
Common causes: Common causes include Battery voltage, Faulty Control Module, Control Module harness is open or shorted.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 171

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Jul 13, 2022

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code C0805 2018 GMC Sierra Description

The vehicle control modules or sensors monitor the system voltage to verify the system voltage is within the normal operating range. Damage to components, and incorrect data can occur when the voltage is out of range. The vehicle has multiple Control Modules that will set this Diagnostic Trouble Code (DTC).

OBDII Code C0805 2018 GMC Sierra - Control Module Power 2 Circuit - AutoCodes.com — C0805 2018 GMC Sierra Code - Control Module Power 2 Circuit

What does this mean?

What are the Possible Causes of the DTC C0805 2018 GMC Sierra?

Battery voltage
Faulty Control Module
Control Module harness is open or shorted
Control Module circuit poor electrical connection

How to Fix the DTC C0805 2018 GMC Sierra?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the C0805 2018 GMC Sierra code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the C0805 2018 GMC Sierra code?

Need more information on how to fix the C0805 2018 GMC Sierra code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the C0805 2018 GMC Sierra code diagnosed by a professional: Find a repair shop in your area

About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about C0805 2018 GMC Sierra Code

1. What does the OBDII code C0805 mean on a 2018 GMC Sierra?

Code C0805 indicates an issue with the "Control Module Power 2 Circuit," meaning the control module is not receiving the proper power supply or has a circuit fault.

2. What are the common symptoms of the C0805 code in a GMC Sierra?

Symptoms may include warning lights on the dashboard, failure of certain electrical components, reduced vehicle performance, or intermittent issues with electronic systems.

3. What causes the C0805 code to appear on a 2018 GMC Sierra?

Common causes include a blown fuse, damaged wiring, faulty connections, a failing control module, or issues with the vehicle's power distribution system.

4. How do I diagnose a C0805 code on my GMC Sierra?

Start by checking the fuses, inspecting the wiring and connectors for damage or corrosion, and using a multimeter to test for proper voltage at the control module.

5. Can I continue driving my GMC Sierra with the C0805 code?

Itâ€™s not recommended to drive for an extended period with this code, as it may lead to further electrical system failures or reduced vehicle functionality.

6. How is the C0805 code usually fixed?

Repairs typically involve replacing blown fuses, repairing or replacing damaged wiring, cleaning corroded connections, or replacing a malfunctioning control module.

7. Does the C0805 code cause other problems in the GMC Sierra?

If unresolved, this code can lead to additional electrical system malfunctions or prevent critical systems from functioning properly.

8. What tools do I need to troubleshoot the C0805 code?

Youâ€™ll need an OBDII scanner, a multimeter for voltage testing, and basic tools for inspecting or replacing wiring and fuses.

9. How much does it cost to fix the C0805 code on a GMC Sierra?

Costs can vary widely depending on the issue, ranging from $10â€“$50 for a fuse replacement to $300â€“$800 or more for a new control module.

10. Can a weak battery cause the C0805 code on a 2018 GMC Sierra?

Yes, a weak or failing battery can result in insufficient power to the control module and trigger the C0805 code. Always check the battery health as part of the diagnosis.